使后退按钮从活动返回到Android中的片段
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【中文标题】使后退按钮从活动返回到Android中的片段【英文标题】：Make back button returns from an activity to a fragment in Android 【发布时间】：2016-10-14 08:10:52 【问题描述】：我正在开发一个 android 应用程序，我有一个名为“更多”的片段，在这个片段中我有诸如“关于我们”、“条款和条件”之类的东西，这些都是正常的活动。我想要做的是，当我点击里面的后退按钮时，例如，关于我们的活动，我想要返回到“更多”片段。我怎样才能做到这一点？这是我在 aboutUs 活动中的内容：
“onBackPressed 方法应该在我单击后退按钮后返回到片段，但它不起作用。应用程序崩溃并且在日志中猫说“你是否在清单中声明了 MoreFragment 活动？ "，但我试图声明它不起作用。
public class AboutUs extends BaseActivity
private ImageView image;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.about_us);
image = (ImageView) findViewById(R.id.imageView2);
image.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
Intent launchactivity = new Intent(AboutUs.this, StartScreenActivity.class);
startActivity(launchactivity);
);
@Override
public void onBackPressed()
Intent intent = new Intent(this,MoreFragment.class);
startActivity(intent);
这是调用Activity的片段：
public class MoreFragment extends Fragment implements View.OnClickListener
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
return inflater.inflate(R.layout.fragment_more, null, false);
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState)
super.onViewCreated(view, savedInstanceState);
TextView lbl1 = (TextView) view.findViewById(R.id.lbl1);
TextView lbl2 = (TextView) view.findViewById(R.id.lbl2);
TextView lbl3 = (TextView) view.findViewById(R.id.lbl3);
TextView lbl4 = (TextView) view.findViewById(R.id.lbl4);
TextView lbl5 = (TextView) view.findViewById(R.id.lbl5);
TextView lbl6 = (TextView) view.findViewById(R.id.lbl6);
TextView lbl7 = (TextView) view.findViewById(R.id.lbl7);
TextView lbl8 = (TextView) view.findViewById(R.id.lbl8);
TextView lbl9 = (TextView) view.findViewById(R.id.lbl9);
ImageView imv1 = (ImageView) view.findViewById(R.id.imv1);
ImageView imv2 = (ImageView) view.findViewById(R.id.imv2);
ImageView imv3 = (ImageView) view.findViewById(R.id.imv3);
ImageView imv4 = (ImageView) view.findViewById(R.id.imv4);
ImageView imv5 = (ImageView) view.findViewById(R.id.imv5);
ImageView imv6 = (ImageView) view.findViewById(R.id.imv6);
ImageView imv7 = (ImageView) view.findViewById(R.id.imv7);
ImageView imv8 = (ImageView) view.findViewById(R.id.imv8);
ImageView imv9 = (ImageView) view.findViewById(R.id.imv9);
ImageView imv10 = (ImageView) view.findViewById(R.id.imv10);
TextView btnSignOut = (TextView) view.findViewById(R.id.lbl10);
lbl1.setOnClickListener(this);
lbl2.setOnClickListener(this);
lbl3.setOnClickListener(this);
lbl4.setOnClickListener(this);
lbl5.setOnClickListener(this);
lbl6.setOnClickListener(this);
lbl7.setOnClickListener(this);
lbl8.setOnClickListener(this);
lbl9.setOnClickListener(this);
imv1.setOnClickListener(this);
imv2.setOnClickListener(this);
imv3.setOnClickListener(this);
imv4.setOnClickListener(this);
imv5.setOnClickListener(this);
imv6.setOnClickListener(this);
imv7.setOnClickListener(this);
imv8.setOnClickListener(this);
imv9.setOnClickListener(this);
btnSignOut.setOnClickListener(this);
View view9 = view.findViewById(R.id.view9);
View view8 = view.findViewById(R.id.view8);
if (!PrefernceHelper.getBoolean(getActivity(), Commons.Constants.USERLOGGEDIN))
imv8.setVisibility(View.INVISIBLE);
lbl8.setVisibility(View.INVISIBLE);
imv10.setVisibility(View.INVISIBLE);
btnSignOut.setVisibility(View.INVISIBLE);
view9.setVisibility(View.INVISIBLE);
view8.setVisibility(View.INVISIBLE);
private void callAllMoreScreen(String type, Class<?> className)
Intent intent = new Intent();
intent.setClass(getActivity(), className);
intent.putExtra(Commons.Constants.LOAD_TYPE_URL, type);
getActivity().startActivity(intent);
private void callAllMoreScreen1(Class<?> className)
Intent intent = new Intent();
intent.setClass(getActivity(), className);
getActivity().startActivity(intent);
@Override
public void onClick(View v)
switch (v.getId())
case R.id.lbl1:
callAllMoreScreen1(AboutUs.class);
break;
case R.id.lbl2:
callAllMoreScreen("contact-us", AllMoreScreenActivity.class);
break;
case R.id.lbl3:
callAllMoreScreen1(TermsConditions.class);
break;
case R.id.lbl4:
callAllMoreScreen1(PrivacyPolicy.class);
break;
case R.id.lbl5:
callAllMoreScreen("faqs", AllMoreScreenActivity.class);
break;
case R.id.lbl6:
callAllMoreScreen("how-it-work", AllMoreScreenActivity.class);
break;
case R.id.lbl7:
callAllMoreScreen("about-foodlebee", AllMoreScreenActivity.class);
break;
case R.id.lbl8:
callAllMoreScreen(" ", PredefinedAddressActivity.class);
break;
case R.id.lbl9:
callAllMoreScreen(" ", TrackyourorderActivity.class);
break;
case R.id.imv1:
callAllMoreScreen1(AboutUs.class);
break;
case R.id.imv2:
callAllMoreScreen("contact-us", AllMoreScreenActivity.class);
break;
case R.id.imv3:
callAllMoreScreen1(TermsConditions.class);
break;
case R.id.imv4:
callAllMoreScreen1(PrivacyPolicy.class);
break;
case R.id.imv5:
callAllMoreScreen("faqs", AllMoreScreenActivity.class);
break;
case R.id.imv6:
callAllMoreScreen("how-it-work", AllMoreScreenActivity.class);
break;
case R.id.imv7:
callAllMoreScreen("about-foodlebee", AllMoreScreenActivity.class);
break;
case R.id.imv8:
callAllMoreScreen(" ", PredefinedAddressActivity.class);
break;
case R.id.imv9:
callAllMoreScreen(" ", TrackyourorderActivity.class);
break;
case R.id.lbl10:
PrefernceHelper.clearAll(getActivity());
callAllMoreScreen("", SignInActivity.class);
getActivity().finish();
break;
这是调用片段的Activity：
public class TabLayoutScreenActivity extends BaseActivity
private TabLayout tabLayout;
private Bundle bundle;
//Bundle bundle;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.tab_screen);
tabLayout = (TabLayout) findViewById(R.id.tab_layout);
ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar); // actionBarSetUp(true);
// getSupportActionBar().setIcon(R.drawable.small_bee);
getSupportActionBar().setDefaultDisplayHomeAsUpEnabled(true);
// getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// getSupportActionBar().setIcon(R.drawable.ic_launcher);
viewPager.setAdapter(new SectionPagerAdapter(getSupportFragmentManager()));
tabLayout.setupWithViewPager(viewPager);
ImageView foodlebee = (ImageView) findViewById(R.id.imageView2);
foodlebee.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
Intent launchactivity = new Intent(TabLayoutScreenActivity.this,StartScreenActivity.class);
startActivity(launchactivity);
);
// bundle = getIntent().getExtras();
@Override
public boolean onCreateOptionsMenu(Menu menu)
getMenuInflater().inflate(R.menu.menu_login, menu);
if (PrefernceHelper.getBoolean(this, Commons.Constants.USERLOGGEDIN))
MenuItem item = menu.findItem(R.id.user_login);
item.setVisible(false);
invalidateOptionsMenu();
return true;
@Override
public boolean onOptionsItemSelected(MenuItem item)
if (item.getItemId() == R.id.user_login)
intentCall(SignInActivity.class, null, 0);
return true;
else if (item.getItemId() == R.id.home)
intentCall(StartScreenActivity.class, null, 0);
finish();
return true;
return false;
@Override
protected void onStart()
super.onStart();
bundle = getIntent().getExtras();
int tabPostion = 0;
if (bundle != null)
tabPostion = bundle.getInt(Commons.Constants.TAB_POSITION, 0);
TabLayout.Tab tab = tabLayout.getTabAt(tabPostion);
tab.select();
public class SectionPagerAdapter extends FragmentPagerAdapter
public SectionPagerAdapter(FragmentManager fm)
super(fm);
@Override
public Fragment getItem(int position)
switch (position)
case 0:
return new ChefFragment();
case 1:
return new OrderFragment();
case 2:
return new BasketFragment();
case 3:
return new MoreFragment();
default:
return new ChefFragment();
@Override
public int getCount()
return 4;
@Override
public CharSequence getPageTitle(int position)
switch (position)
case 0:
return "Chefs";
case 1:
return "Orders";
case 2:
return "Cart";
case 3:
return "More";
default:
return "Chef";
【问题讨论】：
这是在两层之内吗？当您单击 about 片段内的后退按钮时，现在会发生什么？ 在这种情况下不要覆盖onBackPress 方法。它应该会自动工作。
【参考方案1】：
只需finish() onbackpressed 中的当前活动，因此您将返回更多片段，因为前一个活动已经在后台堆栈上。您无需再次启动上一个活动。
此外，您的代码是错误的..您正在尝试启动一个不可能的片段。这就是引发此异常的原因。
像这样更改您的代码：
@Override
public void onBackPressed()
finish();
【讨论】：
我改成了这个，但没有用。它不是回到“更多”片段，而是回到标签中的第一个片段。 您能否分享第一个包含更多片段的活动的代码，然后启动 AboutUs 活动？ 刚刚添加了调用activity的More Fragment。 刚刚添加了活动。 您的问题是由于您的活动的 OnStart 中的代码而发生的。只需将该代码移至 onCreate 即可解决您的问题。以上是关于使后退按钮从活动返回到Android中的片段的主要内容，如果未能解决你的问题，请参考以下文章